daptation resin

of overdenture

abutments

with visible

Russell A. Wicks, DDS,a and Toon-Fuan Chiam, BDS, MDSb University of Texas Health Science Center, Dental School, San Antonio, A visible light cured (VLC) resin material in which polymerization is initiated by a camphoroquinone-amine photo catalyst1 has been available for several years. VLC resins are nontoxic, biocompatible, and have physical properties that meet or exceed the American Dental Association specifications for denture base resins.2 A conventional method, localizing autopolymerizing methyl methacrylate resin to adapt overdenture prostheses to abutments, has been described by Brewer and Morrow.3 VLC tooth-colored. resin material can be substituted in the following technique. Clean, polish, and apply silicon separating media to the abutment teeth. Mark and relieve a 2 to 3 mm area, enveloping the abutment teeth within the overdenture. Place small escape vents in esthetically strategic locations. Apply VLC bonding agent and expose to a curing light for 5 minutes. Heat the VLC resin material, within its packaging, in a water bath at 120’ F to reduce viscosity. Apply appropriate amounts of the warmed resin material within the relieved areas (Fig. 1). Place the overdenture in the mouth and ask the patient to close in centric relation position with moderate biting pressure until correct vertical dimension of occlusion is reestablished. Remove the prosthesis and carefully trim the excess material from the escape vents and tissue interface

aGraduate student, Postgraduate Prosthodontics. bPreceptor, Postgraduate Prosthodontics.

Fig. 1. Warmed VLC resin material areas around overdenture abutments.

THE

JOURNAL

OF PROSTHETIC

DENTISTBY

applied

Tex.

(Fig. 2). Replace the prosthesis in the mouth and ask the patient to perform eccentric movements to functionally load the reline material to the abutments (Fig. 3). Several trails may be needed to form the VLC resin to the desired adaptation. The overdenture may be placed in the water bath intermittently to maintain the proper viscosity of the resin material.

Fig. 2. Excess material and escape vents.

10/4/39144

to relieved

light-cured

Fig. 3. Functional abutments.

trimmed

from tissue interface

load applied to reline material

around

711

TIPS

When adaptation is satisfactory, cure the VLC resin initially for 5 minutes by positioning a hand-held light source on the buccal flanges with the prosthesis in occlusion. After careful intraoral curing through the lingual flanges, remove the overdenture and place it within a VLC curing unit for 10 minutes to insure complete polymerization. Examine the cured resin and adjust for voids, artifacts, or areas of potential tissue impingement. There are advantages of utilizing this technique compared with the conventional methods of abutment activation. Of clinical value is the ease of manipulation of this material without the constraints of a timed set and the absence of adverse soft tissue reactions to exposure to methyl methacrylate free monomer. Potential disadvantages include the cost of equipment and supplies and unproven long-term bond strength between the VLC material, prosthetic teeth, and denture base resins.4

An advantage

of the direct

PROCEDURE 1. Make impressions and diagnostic casts of the patient’s dentition. 2. Make a diagnostic wax-up of the teeth to be restored. (The lower left first and second premolars are used for illustrations in this article.)

1014/39135

712

London, England. Dentistry,

Birmingham

READERS

1. Ogle RE, Sorenson SE, Lewis EA. A new visible light-cured resin system applied to removable prosthodontics. J PROSTHET DENT 1986;56: 497-6.

2. Khan Z, van Fraunhofer JA, Razavi R. The staining characteristics, transverse strength, and microhardness of a visible light-cured denture base material. J PROSTHET DENT 1987;57:384-6. 3. Brewer AA, Morrow RM. Overdentures. 2nd ed. St Louis: CV Mosby, 1980:129,139-40. 4. Clancy JMS, Boyer DB. Comparative bond strength of light-cured, heat-cured, and autopolymerizing denture resins to denture teeth. J PROSTHET DENT 1989;61:457-62. Reprint requests to: DR. RUSSELL A. WICKS POSTGRADUATE PROSTHODONTICS DENTAL SCHOOL UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER 7703 FLOVD CURL DR. SAN ANTONIO, TX 78284-7890

post and core technique

Provisional restorations often have to remain in the mouth several months and must exhibit adequate strength, color stability,l abrasion resistance, and marginal fit. To fulfill these requirements they are best made by use of a more time-consuming indirect technique instead of being formed directly on the mouth.2 It is often necessary to make t&e cast posts and cores for endodontically treated teeth. Provisional restorations made to fit the teeth at the post preparation appointment have to be remade or relined after cementation of the post and core, possibly resulting in a poorer fit and certainly involving more clinical time. The procedure described in this article illustrates how this problem may be avoided when a direct acrylic resin pattern is made for the post and core and an indirect technique for making the provisional restorations is used.

in Restorative

OUR

REFERENCES

N. J. Capp, BDS, FDS, RCS (Edin), MS,a and K. Warren, BDS, FDS, RCS (Edin), London, England, and Birmingham Dental Hospital, Birmingham, England

aPrivate Practice, bSenior Registrar Hospital.

FROM

Dental

DRD,

RCS (Edin)b

3. Prepare the two teeth for porcelain fused-to-metal crowns (Fig. 1). The first premolar requires a post and core buildup. 4. Make an acrylic resin core (Duralay, Reliance Dental Mfg. Co., Worth, Ill.) on a parallel sided plastic burnout post (Para-Post System, Whaledent, New York, N. Y.) (Fig. 1). 5. Make a reversible hydocolloid impression of the mandibular arch, including both prepared teeth with the acrylic resin post and core in place. 6. Pour a cast with a mix of fast-setting impression plaster (Gypsogum Impression Plaster, Associated Dental Products, Swindon, England). 7. Make a stone cast of the diagnostic wax-up (step 2) and use this to form a matrix. 8. Make aprovisionalrestorationof polymethylmethacrylate resin (Meyerson crown and bridge acrylic, Meyerson Tooth Corp., Chicago Ill.). A. Paint tinfoil substitute over the plaster cast, including the dies of the preparations. B. Make a mix of the resin, following the manufacturer’s instructions. C. Fill the matrix with resin. D. Seat the matrix on the cast with two preparations, place it in a pressure pot, and cure it for five minutes. 9. Remove the direct pattern from the first premolar. 10. Trim, seat, and adjust the occlusion; finish and polish the provisional restoration. 11. Cement the provisional restoration after blocking out

OCTOBER

1992

VOLUME

68

NUMBER

4

Adaptation of overdenture abutments with visible light-cured resin.

daptation resin of overdenture abutments with visible Russell A. Wicks, DDS,a and Toon-Fuan Chiam, BDS, MDSb University of Texas Health Science Ce...
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